A multi-ignition coil control system includes a spark plug including first and second center electrodes, and first and second ground electrodes spaced apart from the center electrodes by a predetermined distance, a first ignition coil including a primary coil, and a secondary coil in which a discharge current is generated by electromagnetic induction with the primary coil, and a second ignition coil including a primary coil, and a secondary coil in which a discharge current is generated by electromagnetic induction with the primary coil, wherein one end of the secondary coil of the first ignition coil and one end of the secondary coil of the second ignition coil are electrically connected to one of the center electrodes, and the other end of the secondary coil of the first ignition coil and the other end of the secondary coil of the second ignition coil are electrically connected to the other of the center electrodes.

A spark plug includes a metal body member formed of a metal material, an insulating body member provided inside the metal body member and formed of an insulating material, a pair of central electrodes provided inside the insulating body member and having different polarities, and a ground electrode extending from the metal body member between a pair of central electrodes.

To suppress a failure of ignition of a fuel caused by a spark plug while suppressing wear of an electrode of the spark plug in an internal combustion engine. A control device 1 for an internal combustion engine includes an ignition control unit that controls energization of an ignition coil 300 that applies electric energy to a spark plug 200 that discharges in a cylinder 150 of an internal combustion engine 100 to ignite a fuel. The ignition control unit continuously transmits a first pulse signal (pulse signal for corona discharge) to an igniter connected to the ignition coil 300 before dielectric breakdown between electrodes of the spark plug 200, and continuously transmits a second pulse signal (pulse signal for arc discharge) to the igniter after the dielectric breakdown between the electrodes of the spark plug 200 to control the energization of the ignition coil 300. At this time, a period of the pulse signal for corona discharge is shorter than a period of the pulse signal for arc discharge.

Failure in ignition of a fuel by an ignition plug is reduced, and, at the same time, wearing of electrodes of the ignition plug in an internal combustion engine is suppressed. A control device 1 for an internal combustion engine includes an ignition control unit that controls energization of an ignition coil 300 that supplies electric energy to an ignition plug 200 that discharges in a cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit controls the energization of the ignition coil 300 such that first electric energy is released from the ignition coil 300 and second electric energy is released in superposition with the first electric energy. At this time, the energization of the ignition coil 300 is controlled such that releasing of the second electric energy is stopped at a timing that depends on a state of gas around the ignition plug 200 so that the discharge of the ignition plug 200 is stopped.

An ignition system and a method for operating an ignition system for an internal combustion engine are provided, including a primary voltage generator and a boost converter for generating an ignition spark. An ascertainment of a voltage requirement for the ignition spark is followed by a modification of a switch-on time of the boost converter relative to a switch-off time of the primary voltage generator.

Disclosed is a method for determining a need for changing a spark plug of a combustion engine, comprising the following steps: monitoring a current flowing through the spark plug, analyzing the current and thereby determine a time interval that is indicative for the time between application of a voltage to the spark plug and formation of an arc discharge between electrodes of the spark plug, creating a signal indicative of the need to change the spark plug if the duration of the determined time interval is outside predefined bounds.

Disclosed is a method for determining a need for changing a spark plug of a combustion engine, comprising the following steps: monitoring a current flowing through the spark plug, analyzing the current and thereby determine a time interval that is indicative for the time between application of a voltage to the spark plug and formation of an arc discharge between electrodes of the spark plug, creating a signal indicative of the need to change the spark plug if the duration of the determined time interval is outside predefined bounds.

An ignition coil for an internal combustion engine has a primary coil and a secondary coil, a case, a high voltage connection terminal, and a conduction terminal. The high voltage connection terminal is accommodated in the case in a state being sealed by a filling resin. The high voltage connection terminal is disposed in a state inclined an aligned direction of the secondary coil and the conduction terminal, and is configured to be elastically deformable. The conduction terminal includes an engaging part for engaging a terminal distal end portion of the high voltage connection terminal and a supporting part for supporting a terminal intermediate portion of the high voltage connection terminal which is a portion closer to a connecting portion with the secondary coil than the terminal distal end portion is. In the aligned direction, the terminal distal end portion contacts with the engaging part from a side opposite to a secondary coil side, and the terminal intermediate portion contacts with the supporting part from the secondary coil side.

An ignition coil for an internal combustion engine has a primary coil and a secondary coil, a case, a high voltage connection terminal, and a conduction terminal. The high voltage connection terminal is accommodated in the case in a state being sealed by a filling resin. The high voltage connection terminal is disposed in a state inclined an aligned direction of the secondary coil and the conduction terminal, and is configured to be elastically deformable. The conduction terminal includes an engaging part for engaging a terminal distal end portion of the high voltage connection terminal and a supporting part for supporting a terminal intermediate portion of the high voltage connection terminal which is a portion closer to a connecting portion with the secondary coil than the terminal distal end portion is. In the aligned direction, the terminal distal end portion contacts with the engaging part from a side opposite to a secondary coil side, and the terminal intermediate portion contacts with the supporting part from the secondary coil side.

An engine ignition system for a spark-ignited engine includes a sparkplug and a control system having primary ignition circuitry, secondary ignition circuitry coupled with electrodes of the sparkplug, and sensing circuitry. A control device determines a timing of spark production based on a pattern of varying of an electrical property in the primary ignition circuitry. An inflection point in a sensed current signal may be detected to determine the timing.